MSDN Documentation - App Services Networking

Understanding Networking in Azure App Services

Azure App Services provides a robust and scalable platform for hosting web applications, APIs, and mobile backends. Networking is a critical aspect of deploying and managing your applications, ensuring secure and efficient communication. This documentation dives deep into the networking features available for App Services.

Core Networking Concepts

When you deploy an application to Azure App Services, it runs within a network environment managed by Azure. Understanding these concepts is key to effectively configuring your app's network access and security.

Virtual Network Integration

Virtual Network (VNet) integration allows your App Service app to securely access resources within an Azure Virtual Network. This is crucial for applications that need to communicate with other services like Azure SQL Database, Azure Storage, or virtual machines without exposing those resources to the public internet.

How it works: VNet integration creates a network route from your App Service to your VNet, enabling private access.
Benefits: Enhanced security, simplified network management, and access to private endpoints.

Private Endpoints

Private Endpoints provide a secure way to access your App Service from within your private network (e.g., on-premises via VPN/ExpressRoute or within an Azure VNet). They assign a private IP address to your App Service within your chosen VNet, eliminating the need for public internet exposure for inbound traffic.

Use Cases: Connecting to App Services from on-premises networks, isolating App Services within a VNet.
Configuration: Requires setup of a VNet, subnet, and the Private Endpoint resource itself.

Access Restrictions

You can control inbound access to your App Service by configuring IP-based access restrictions. This allows you to specify which IP addresses or IP ranges are permitted to access your application.

Important: Access restrictions are evaluated in order. The first rule that matches the incoming request's source IP determines whether access is allowed or denied.

You can set up rules to:

Allow traffic from specific IP addresses.
Allow traffic from VNet integrated subnets.
Deny all other traffic.

Custom Domains and SSL Certificates

Securing your application with a custom domain and SSL/TLS certificate is essential for building trust with your users. App Services supports binding custom domains and managing SSL certificates.

Domain Validation: Requires DNS CNAME or TXT records.
SSL Binding: Supports uploading your own certificates or using App Service Managed Certificates.

Advanced Networking Features

Beyond the fundamentals, App Services offers advanced features to cater to complex networking requirements.

Hybrid Connections

Hybrid Connections provide a secure bridge between your App Service and on-premises systems or other cloud environments. They use the Azure Relay service to enable communication without requiring complex firewall configurations or VPNs.

Tip: Hybrid Connections are ideal for scenarios where you need to connect to databases or other services running within your corporate network.

Traffic Manager and Front Door

For high availability, performance optimization, and global routing, consider integrating your App Services with Azure Traffic Manager or Azure Front Door. These services provide:

Traffic Manager: DNS-based traffic load balancing.
Azure Front Door: Global, scalable entry-point that uses the Microsoft global edge network to create fast, secure, and widely scalable web applications.

Configuration Examples

Here's a basic example of how you might configure VNet Integration using the Azure CLI.


# Ensure you have a VNet and a subnet ready
az network vnet subnet create --resource-group MyResourceGroup --vnet-name MyVNet --name AppServiceSubnet --delegations Microsoft.Web/serverfarms --service-endpoints Microsoft.Web

# Integrate your App Service with the VNet
az webapp vnet-integration add --resource-group MyResourceGroup --name MyApp --vnet AppServiceSubnet --subnet AppServiceSubnet

API Reference

For detailed information on managing networking configurations programmatically, refer to the following API documentation:

Best Practices

Always use VNet integration or Private Endpoints for accessing backend resources.
Implement IP-based access restrictions to limit exposure.
Secure your custom domains with SSL/TLS certificates.
Leverage Traffic Manager or Front Door for global deployments and high availability.

By understanding and implementing these networking features, you can build secure, reliable, and high-performing applications on Azure App Services.